Papers by Giovanna della Porta
Chemical Engineering & Technology, Aug 6, 2003
New supercritical fluid based techniques for particle design are reviewed in this paper. Particul... more New supercritical fluid based techniques for particle design are reviewed in this paper. Particular attention will be given to a new and promising technique that uses supercritical fluids to assist atomization processes. Using this new and versatile process, several water soluble compounds that cannot be treated by traditional supercritical fluid based techniques can be successfully micronized. Lipophilic compounds can also be successfully processed.
The aim of the present work is to demonstrate the c apabilities of the continuous supercritical e... more The aim of the present work is to demonstrate the c apabilities of the continuous supercritical emulsion extraction technology (SEE-C ) for the production of poly-lactic-coglycolic acid (PLGA) microspheres with an engineered size and dis tribution charged with different active principles. Indeed, varying the em ulsion formulation and the droplet dimensions, microspheres charged with different act ive principles and with different mean diameters can be produced in few minutes by SEE-C o perating in a pressure range of 80-120 bar at 38°C with a liquid/gas flow-rate ratio of 1/ 10. For all the systems studied, a detailed characterization of the produced microspheres in te rms of morphology and size distribution is proposed together with a study of the release profi les of the entrapped active principles.
Acta horticulturae, Apr 1, 1999
Journal of CO2 utilization, Jul 1, 2017
The extraction of pyrethrins from chrysanthemum flowers has been performed using supercritical CO... more The extraction of pyrethrins from chrysanthemum flowers has been performed using supercritical CO 2 (SC-CO 2) extraction coupled to fractional separation, with the aim of producing complete and selective extraction of these insecticidal principles. 90 bar, 40°C were selected as the operative conditions for a first step of extraction, to work at moderate SC-CO 2 density; two separators in series operating at −10°C and at a pressure equal to that of extraction, and 25°C, 15 bar, were used for fractional separation, respectively. A second SC-extraction step, performed at 200 bar 40°C, demonstrated that many undesired compounds were co-extracted at these process conditions. The comparison with liquid extraction, using petroleum ether, showed that using SC-CO 2 and an exhaustive processing, 30% more pyrethrins were extracted. Using the fractional separation, the produced extracts contained about 99% w/w pyrethrins if the process was stopped after about 80 min. Another suggested duration of the extraction process can be set at about 250 min, at which about 63% w/w pyrethrins were contained in the extracted material. The adopted process strategy could be readily extended to the supercritical processing of several other materials and to the industrial scale.
Journal of Supercritical Fluids, Oct 1, 2017
Supercritical fractional extraction and separation scheme, was used to process Artemisia annua L.... more Supercritical fractional extraction and separation scheme, was used to process Artemisia annua L., producing extracts enriched in active antimalarial principles. The best results were obtained when extraction was performed at 100 bar, 40°C and the first separator was operated at the same pressure and at −7°C. Paraffinic co-extracted compounds were selectively recovered in the first separator, confirming the efficiency of the fractional cooling separation and a concentration of 35% w/w of active compounds was obtained in the second separator. Artemisinin was the major active compound in the extract; but, other two active compounds, artemisin and dehydroartemisinin, were also largely found. Other co-extracted compounds belonged to Artemisia essential oil. Different SC-CO 2 flow rates were tested: an increase from 0.8 to 1.2 kg/h did not determine appreciable variations of the extraction rate of the various compounds, indicating that internal mass transfer resistance mainly controlled the extraction process.
Industrial & Engineering Chemistry Research, Jan 23, 1998
Supercritical antisolvent precipitation (SAS) is based on the fast dissolution of a liquid soluti... more Supercritical antisolvent precipitation (SAS) is based on the fast dissolution of a liquid solution in a supercritical fluid. This technique has been tested to produce nanoparticles of yttrium, samarium, and neodymium acetates to be used as precursors of high-temperature superconductors. Particles of various morphologies were produced at different expansion levels of the liquid solution. Nanoparticles down to about 100 nm were obtained at very large expansion levels, whereas very large aggregates (balloons) with the diameter of several microns were produced at intermediate expansion levels. The influence of several process parameters on particle diameter and particle size distribution was studied. Among SAS process parameters, pressure, temperature, concentration of the liquid solution, and different liquid solvents were tested.
Current Pharmaceutical Design, Oct 3, 2017
The foundation of tissue engineering for either therapeutic or diagnostic applications is the abi... more The foundation of tissue engineering for either therapeutic or diagnostic applications is the ability to exploit living cells. Tissue engineering utilizes living cells as engineering materials implanted, seeded or bioplotted into an artificial structure capable of supporting three-dimensional tissue formation. These structures, typically called scaffolds, are critical, both ex vivo and in vivo, to influence their own microenvironments. Scaffolds can serve the following purposes: allow cell attachment and migration, deliver and retain cells and biochemical factors, enable diffusion of vital cell nutrients or expressed products, exert certain mechanical and biological influences to modify the behaviour of the cell phase. Traditional tissue engineering strategies typically employ a "top-down" approach, in which cells are seeded on a biodegradable three dimensional monolithic polymeric scaffold. More recently they have been updated by a "bottom- up" approach, also known as modular tissue engineering; it is aimed to address the challenge of recreating bio-mimetic structures by designing structural micro-features to build modular tissues, used as building blocks to re-create larger ones. These two different approaches will require scaffolds with given characteristics obtainable by choosing different fabrication technologies. Conventional and innovative supercritical technologies for monolithic scaffold production or biopolymer micro/nano devices will be discussed in this chapter. Some examples of bone and cartilage tissue engineering produced by using modular scaffold will be also discussed, as well as the fabrication of artificial extracellular matrix for spatio-temporally delivery of biological and mechanical signal to address cell fate.
Biotechnology and Bioengineering, Apr 8, 2019
Poly‐lactic‐co‐glycolic acid (PLGA) microcarriers (0.8 ± 0.2 μm) have been fabricated with a load... more Poly‐lactic‐co‐glycolic acid (PLGA) microcarriers (0.8 ± 0.2 μm) have been fabricated with a load of 20 μg/gPLGA by an emulsion‐based‐proprietary technology to sustained deliver human bone morphogenetic protein 2 (hBMP2), a growth factor largely used for osteogenic induction. hBMP2 release profile, measured in vitro, showed a moderate “burst” release of 20% of the load in first 3 days, followed by a sustained release of 3% of the load along the following 21 days. PLGA microbeads loaded with fluorescent marker (8 mg/gPLGA) and hydroxyapatite (30 mg/gPLGA) were also fabricated and successfully dispersed within three‐dimensional (3D) alginate scaffold (Ca‐alginate 2% wt/wt) in a range between 50 and 200 mg/cm3; the presence of microcarriers within the scaffold induced a variation of its stiffness between 0.03 and 0.06 MPa; whereas the scaffold surface area was monitored always in the range of 190–200 m2/g. Uniform microcarriers dispersion was obtained up to 200 mg/cm3; higher loading values in the 3D scaffold produced large aggregates. The release data and the surface area were, then, used to simulate by finite element modeling the hBMP2 mass transfer within the 3D hydrogel bioengineered with stem cells, in dynamic and static cultivations. The simulation was developed with COMSOL Multiphysics® giving a good representation of hBMP2 mass balances along microbeads (bulk eroded) and on cell surface (cell binding). hBMP2 degradation rate was also taken into account in the simulations. hBMP2 concentration of 20 ng/cm3 was set as a target because it has been described as the minimum effective value for stem cells stimulation versus the osteogenic phenotype. The sensitivity analysis suggested the best microbeads/cells ratio in the 3D microenvironment, along 21 days of cultivations in both static and dynamic cultivation (perfusion) conditions. The simulated formulation was so assembled experimentally using human mesenchymal stem cells and an improved scaffold stiffness up to 0.09 MPa (n = 3; p ≤ 0.01) was monitored after 21 days of cultivation; moreover a uniform extracellular matrix deposition within the 3D system was detected by Von Kossa staining, especially in dynamic conditions. The results indicated that the described tool can be useful for the design of 3D bioengineered microarchitecture by quantitative understanding.
Journal of Pharmaceutical Sciences, Aug 1, 2017
DP, Novel superparamagnetic micro-devices based on magnetised PLGA/PLA microparticles obtained by... more DP, Novel superparamagnetic micro-devices based on magnetised PLGA/PLA microparticles obtained by supercritical fluid emulsion and coating by carboxybetaine-functionalised chitosan allowing the tuneable release of therapeutics,
Pure and Applied Chemistry, Aug 1, 2001
Micronized powders are of interest in many industrial fields; pharmaceuticals, catalysts, pigment... more Micronized powders are of interest in many industrial fields; pharmaceuticals, catalysts, pigments, and biopolymers, for example, are some categories of products that can be used as micro-sized particles. Traditional techniques used to produce micronic powders are based on high-temperature reactions that require high energies, on jet milling that is characterized by low efficiencies and mechanical stress, and on liquid solvents precipitation that has a poor control on particle size and can pollute the product. Generally, the control of the powder size and the span of its distribution are still very approximate. In the last few years, several supercritical fluids-based techniques have been proposed for the production of micronic and nanometric particles. These processes try to take advantage of some specific properties of gases at supercritical conditions such as enhanced solubilization power and its modulation, large diffusivities, solventless or organic solvent reduced operation, and the connected possibility of controlling powder size and distribution. Techniques like the rapid expansion of supercritical solutions (RESS), supercritical antisolvent precipitation (SAS), particle generation from gas-saturated solutions (PGSS), and new atomization processes have been critically reviewed in this work.
Powder Technology, 2001
ABSTRACT
International Journal of Molecular Sciences
Electrospun systems are becoming promising devices usable for topical treatments. They are eligib... more Electrospun systems are becoming promising devices usable for topical treatments. They are eligible to deliver different therapies, from anti-inflammatory to antitumoral. In the current research, polycaprolactone electrospun membranes loaded with synthetic and commercial antitumoral active substances were produced, underlining how the matrix-filler affinity is a crucial parameter for designing drug delivery devices. Nanofibrous membranes loaded with different percentages of Dacarbazine (the drug of choice for melanoma) and a synthetic derivative of Dacarbazine were produced and compared to membranes loaded with AuM1, a highly active Au-complex with low affinity to the matrix. AFM morphologies showed that the surface profile of nanofibers loaded with affine substances is similar to one of the unloaded systems, thanks to the nature of the matrix-filler interaction. FTIR analyses proved the efficacy of the interaction between the amidic group of the Dacarbazine and the polycaprolactone...
Frontiers in Bioengineering and Biotechnology
In this work, a 3D environment obtained using fibrin scaffold and two cell populations, such as b... more In this work, a 3D environment obtained using fibrin scaffold and two cell populations, such as bone marrow-derived mesenchymal stem cells (BM-MSCs), and primary skeletal muscle cells (SkMs), was assembled. Peripheral blood mononuclear cells (PBMCs) fraction obtained after blood filtration with HemaTrate® filter was then added to the 3D culture system to explore their influence on myogenesis. The best cell ratio into a 3D fibrin hydrogel was 1:1 (BM-MSCs plus SkMs:PBMCs) when cultured in a perfusion bioreactor; indeed, excellent viability and myogenic event induction were observed. Myogenic genes were significantly overexpressed when cultured with PBMCs, such as MyoD1 of 118-fold at day 14 and Desmin 6-fold at day 21. Desmin and Myosin Heavy Chain were also detected at protein level by immunostaining along the culture. Moreover, the presence of PBMCs in 3D culture induced a significant downregulation of pro-inflammatory cytokine gene expression, such as IL6. This smart biomimetic en...
Pharmaceutics
Herein, the synthesis and characterization of a novel composite biopolymer scaffold—based on equi... more Herein, the synthesis and characterization of a novel composite biopolymer scaffold—based on equine type I collagen and hyaluronic acid—were described by using a reaction in heterogeneous phase. The resulting biomimetic structure was characterized in terms of chemical, physical, and cytotoxicity properties using human-derived lymphocytes and chondrocytes. Firstly, FT-IR data proved a successful reticulation of hyaluronic acid within collagen structure with the appearance of a new peak at a wavenumber of 1735 cm−1 associated with ester carbonyl stretch. TGA and DSC characterizations confirmed different thermal stability of cross-linked scaffolds while morphological analysis by scanning electron microscopy (SEM) suggested the presence of a highly porous structure with open and interconnected void areas suitable for hosting cells. The enzymatic degradation profile confirmed scaffold higher endurance with collagenase as compared with collagen alone. However, it was particularly interest...
International Journal of Pharmaceutics
International Journal of Molecular Sciences
Two non-commercial metallic Au-based complexes were tested against one of the most aggressive mal... more Two non-commercial metallic Au-based complexes were tested against one of the most aggressive malignant melanomas of the skin (MeWo cells), through cell viability and time-lapse live-cell imaging system assays. The tests with the complexes were carried out both in the form of free metallic complexes, directly in contact with the MeWo cell line culture, and embedded in fibers of Polycaprolactone (PCL) membranes produced by the electrospinning technique. Membranes functionalized with complexes were prepared to evaluate the efficiency of the membranes against the melanoma cells and therefore their feasibility in the application as an antitumoral patch for topical use. Both series of tests highlighted a very effective antitumoral activity, manifesting a very relevant cell viability inhibition after both 24 h and 48 h. In the case of the AuM1 complex at the concentration of 20 mM, melanoma cells completely died in this short period of time. A mortality of around 70% was detected from the...
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Papers by Giovanna della Porta